EEPORT ON THE TETKACTINELLIDA. 
187 
as Stelletta grubii, from Holyhead ; the spicules are very similar to those of Schmidt’s 
type, and I have no doubt as to the correctness of the identification. I was not able to 
make out the characters of the cortex. 
Genus 10 . Dragmastra, Sollas. 
Cortex similar to that of Stelletta, but with the middle, or collenchymatous layer 
crowded with orthodragmas. 
Dragmastra normani, Sollas. 
Stelletta Normani, Sollas, Aim. and Mag. Nat. Hist., ser. 5, vol. v. p. 130, pis. vi., vii., 
1880. 
Sponge somewhat spherical, becoming depressed, cake-like with age ; sessile, attached ; 
surface hispidated by oxeas and dichotrisenes ; oscules not observed ; pores in sieves 
generally distributed ; cortex 1;7 mm. thick. 
Spicules. — I. Megascleres. 1. Oxea, 6‘0 by 0‘064 mm. 2.. Dichotrisene, 3;2 by 
0’094 mm., protocladi 0:39 mm. long, deuterocladi 0'57 mm. long. 3. Protrisene, 5‘5 by 
0‘032 mm. 4. Anatrisene, 5 5 by 0’032 mm., cladi 0.'127 mm. long, chord 0127 mm. 
II. Microscleres. 5. Orthodragma, 0‘05 by 0'02 mm. 6. Oxyaster, 0‘019 to 0’033 
mm. in diameter. 7. Chiaster, a small centrum and numerous bacillary actines, some- 
times faintly tylote, 0'012 mm. in diameter. 
Colour . — Grey externally, yellowish -white within. 
Habitat. — Kors Fjord, Norway; depth, 180 fathoms (Norman). 
Remarks. — The orthodragmas not only form a special layer in the cortex, but are 
thickly scattered through the choanosome, like the sterrasters of the Geodiidse. The large 
problematical oval cells [loc. cit., p. 139) mentioned as surrounding the subcortical crypts 
are, as I now believe, the scleroblasts of the orthodragmas. 
Genus 11. Aurora, n. gen. 
The cortex not difierentiated into two layers ; densely crowded with large spher- 
asters. 
Aurora glohostellata (Carter). 
Stelletta glohostellata, Carter, Aim. and Mag. Nat. Hist., ser. 5, vol. xi. p. 353, pi. xiv. 
fig. 6, 1883. 
Sponge. — Surface smooth, raised into low, undulating ridges, united to form a 
reticulation ; pores singly situated in its meshes ; oscules congregated. Cortex, 0'26 mm. 
thick. 
